两株乳酸菌发酵上清液对E.coli作用分析及培养条件优化
Analysis and optimization of against E.coli by fermented supernatant from two Lactobacillus
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摘要: 以植物乳杆菌和保加利亚乳杆菌为研究对象,以大肠杆菌为指示菌,通过琼脂扩散法首先分析植物乳酸杆菌和保加利亚乳酸杆菌的发酵上清液对大肠杆菌的抑菌活性差异,然后再观察不同培养温度、葡萄糖浓度、pH和培养时间对植物乳杆菌发酵上清液抑菌效果的影响。结果显示,植物乳杆菌在35℃,8%葡萄糖,pH为9时,发酵上清液抑菌效果较好。经过正交优化实验得出最佳条件组合为:培养温度35℃,培养基pH7,葡萄糖浓度8%,培养时间36h,抑菌圈直径为(1.451±0.016)cm。研究还发现,保加利亚乳杆菌发酵上清液对大肠杆菌无抑制作用。Abstract: In this study, using E.coli as the indicator bacteria the antibacterial activity against E.coli of the fermented supernatant of Lactobacillus plantarum and Lactobacillus bulgaricus by the agar diffusion was investgated.Then, the effect of culture temperature, glucose concentration, pH and cultivating time on the antibacterial activity of the Lactobacillus plantarum were studied.The results showed that when Lactobacillus plantarum were incubated at 35℃, glucose concentration 8% and pH9, the antibacterial activity of its fermentation supernatant fluid was pretty good.Orthogonal test was used to analyze the optimum culture conditions for planting Latcobacillus.The optimum culture conditions for its antibacterial activity were estimated to be, cultivation temperature at 35℃, incubating for 36h, glucose concentration 8% and pH7, and the bacteriostatic circle was measured at (1.451±0.016) cm in diameter.In addition, the results of this study suggested that Lactobacillus bulgaricus had no bacteriostasis to E.coli.
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